Evidence for the emergence of a type-1-like immune response in intestinal mucosa of calves recovering from cryptosporidiosis

This study was undertaken to characterize the mucosal response to Cryptospo ridium parvum in infected calves that had recovered from diarrhea. Flow cyt ometric surface phenotypes of lamina propria lymphocyte (LPL) suspensions f rom infected calves and age-matched controls revealed the presence of a sig nificantly larger proportion of CD25(+) LPL in infected calves than in cont rols. Freshly isolated LPL from infected calves expressed more iNOS and int erferon (IFN)-gamma than did controls. Infected calves excreted IgG(1) and IgG(2) isotype antibodies to C. parvum p23 by the end of the experiment. Mo reover, immunohistochemistry of ileal sections revealed the presence of IgG (1)(+) and IgG(2)(+) B lymphocytes in the villi and IgG(1)(+) but not IgG(2 )(+) B lymphocytes in continuous Peyer's parch nodules. These data are cons istent with the emergence of a type-1-like mucosal immune response in termi nal ileal mucosa as calves recover from cryptosporidiosis.